With frequent occurrences of natural calamities, such as, earthquake, floods, tsunami, cyclone, tornado, volcano, fire hazards, epidemic prone diseases etc., Early Warning Systems (EWS) are in great demand. Typically, an Early Warning System (EWS) is a timely surveillance system, which collects information about natural calamities and triggers warning alerts (also referred as Early Warning Message (EWM)) to public in a geographical area of the natural calamity. However, traditional EWS are rudimentary and are of passive nature such as television, radio and World Wide Web (WWW) etc. EWS based on such public broadcast mechanisms are often unreliable as the person likely to be affected by a calamity need to be attentively watching the television or to be listening to the radio as the news of the likely calamity is being broadcast. In such cases, news of impeding danger not reaching a person likely to be affected by the forthcoming calamity is extremely high.
Until very recently the above were the only modes of conveying the news of the imminent calamity. In the recent years, a few active EWS have been proposed to overcome the passiveness inherent in the traditional modes of conveying warning messages. For example, the automatic telephone notifications of locations in a tornado path to people whose contact numbers are registered with the early warning system. However, there are only a handful of such active early warning systems and are largely associated with a number of drawbacks. For instance, when an attempt is made to contact a large set of people in a short time interval, network bandwidth becomes a bottleneck.
A further drawback, in case of automatic telephone notification is that a user (also referred as subscriber) needs to register his telephone number with the EWS and if he fails to do so, he is not informed of calamity even if he is in the affected region. Furthermore, the EWS, typically, continues to deliver EWM to a user if he has moved out of the affected region and is not currently present therein. Such situations are commonly encountered in tourist destinations.
In yet another scenario, since the subscriber's telephone number is linked to the zip code and the telephone prefix information, the aforementioned EWS will repeatedly try to contact and notify the subscriber even though the subscriber is not physically located in the area (the area to be affected by the calamity), thus wasting network resources and causing inconvenience to the subscriber. In other words, on one hand the EWS will necessarily try to establish contact with the subscriber even though the subscriber is not physically present at the affected region. On the other hand, the EWS will fail to inform subscribers whose zip code information and the telephone prefix information does not match that of the geographic area of his current location.
Still further, use of existing EWS does not guarantee that the intended subscriber has indeed received the news i.e. there is no confirmation that the message has indeed been delivered and has been read by the subscriber. For example, in the case of flush floods during the night time, it is quite likely that most of the people would be asleep and may not take the call or may have switched their cell phones off. In such instances, the current EWS make no attempt to reach these persons through alternative means.
Furthermore, in any disaster management scenario, there may be situations where people
may be crossing affected regions. The EWS will fail to notify EWM to such people as telephone numbers with zip code and the telephone prefix information do not belong to the affected regions and are not registered with the EWS. Still further, existing EWS do not address network bandwidth becoming a bottleneck when extremely large set of people need to be addressed in shortest possible time interval.
Thus, there is a requirement of a robust, holistic and cost effective EWS designed to overcome the above-mentioned limitations that delivers EWM efficiently where subscribers are geographically dispersed and message is to be delivered in the shortest possible time.